U.S. patent application number 11/617497 was filed with the patent office on 2008-07-03 for ultrasonic liquid treatment system.
This patent application is currently assigned to KIMBERLY-CLARK WORLDWIDE, INC.. Invention is credited to Thomas David Ehlert, Robert Allen Janssen, John Gavin MacDonald, Earl C. McCraw, Patrick Sean McNichols.
Application Number | 20080159063 11/617497 |
Document ID | / |
Family ID | 39319696 |
Filed Date | 2008-07-03 |
United States Patent
Application |
20080159063 |
Kind Code |
A1 |
Janssen; Robert Allen ; et
al. |
July 3, 2008 |
ULTRASONIC LIQUID TREATMENT SYSTEM
Abstract
In a system and process for ultrasonically treating a liquid
having a thermal conductivity, an elongate treatment chamber
housing has an inlet and an outlet such that liquid flows
longitudinally through an interior space of the chamber from the
inlet to the outlet. At least part of the interior space of the
chamber housing is filled with a bed of particles having a thermal
conductivity substantially greater than that of the liquid whereby
a ratio of the thermal conductivity of the particles to the thermal
conductivity of the liquid is in the range of about 2:1 to about
400:1. An elongate ultrasonic waveguide assembly extends
longitudinally within the interior space of the housing and is
operable at a predetermined ultrasonic frequency to generate
mechanical ultrasonic vibration within the housing in direct
contact with the liquid flowing therein as the liquid flows through
the bed of particles.
Inventors: |
Janssen; Robert Allen;
(Alpharetta, GA) ; Ehlert; Thomas David; (Neenah,
WI) ; MacDonald; John Gavin; (Decatur, GA) ;
McCraw; Earl C.; (Duluth, GA) ; McNichols; Patrick
Sean; (Hortonville, WI) |
Correspondence
Address: |
Christopher M. Goff (27839);ARMSTRONG TEASDALE LLP
ONE METROPOLITAN SQUARE, SUITE 2600
ST. LOUIS
MO
63102
US
|
Assignee: |
KIMBERLY-CLARK WORLDWIDE,
INC.
Neenah
WI
|
Family ID: |
39319696 |
Appl. No.: |
11/617497 |
Filed: |
December 28, 2006 |
Current U.S.
Class: |
366/118 ;
366/127 |
Current CPC
Class: |
B01J 19/10 20130101;
B01F 11/0258 20130101; B01F 5/0695 20130101; B01J 2219/1943
20130101; B01J 2219/089 20130101; B01J 19/008 20130101; B01F 5/0696
20130101; B01J 8/40 20130101; B01J 2219/185 20130101 |
Class at
Publication: |
366/118 ;
366/127 |
International
Class: |
B01F 11/02 20060101
B01F011/02 |
Claims
1. An ultrasonic treatment chamber for ultrasonically treating a
liquid having a thermal conductivity, said treatment chamber
comprising: an elongate housing having longitudinally opposite ends
and an interior space, the housing being generally closed at said
longitudinal ends and having an inlet port for receiving liquid
into the interior space of the housing and an outlet port through
which liquid is exhausted from the housing following ultrasonic
treatment of the liquid, the outlet port being spaced
longitudinally from the inlet port such that liquid flows
longitudinally within the interior space of the housing from the
inlet port to the outlet port, an elongate ultrasonic waveguide
assembly extending longitudinally within the interior space of the
housing and being operable at a predetermined ultrasonic frequency
to ultrasonically energize liquid flowing within the housing, the
waveguide assembly comprising an elongate ultrasonic horn disposed
intermediate the inlet port and the outlet port of the housing and
having an outer surface located for contact with liquid flowing
within the housing from the inlet port to the outlet port; and a
bed of particles disposed within the interior space of the housing
transversely intermediate the waveguide assembly and the chamber
housing, said particles having a thermal conductivity substantially
greater than that of the liquid flowing within said housing, a
ratio of the thermal conductivity of the particles to the thermal
conductivity of said liquid being in the range of about 2:1 to
about 400:1.
2. The ultrasonic treatment chamber set forth in claim 1 wherein
the ratio of the thermal conductivity of said particles to the
thermal conductivity of said liquid is in the range of about 5:1 to
about 400:1.
3. The ultrasonic treatment chamber set forth in claim 1 wherein
the ratio of the thermal conductivity of said particles to the
thermal conductivity of said liquid is in the range of about 50:1
to about 400:1.
4. The ultrasonic treatment chamber set forth in claim 1 wherein
the particles have a thermal conductivity of at least about 5
w/m-K.
5. The ultrasonic treatment chamber set forth in claim 1 wherein
the particles have a thermal conductivity of at least about 30
w/m-K.
6. The ultrasonic treatment chamber set forth in claim 1 wherein
the particles have a thermal conductivity of at least about 100
w/m-K.
7. The ultrasonic treatment chamber set forth in claim 1 wherein
the waveguide assembly has a terminal end spaced longitudinally
from the outlet port of the housing, the chamber further comprising
a standing wave member disposed within the housing longitudinally
intermediate the outlet port of the housing and the terminal end of
the waveguide assembly, said standing wave member being spaced from
the terminal end of the waveguide assembly so as to define an
acoustic standing wave therebetween upon operation of the waveguide
assembly at said predetermined ultrasonic frequency.
8. The ultrasonic treatment chamber set forth in claim 7 wherein
the standing wave member comprises a reflector.
9. The ultrasonic treatment chamber set forth in claim 1 wherein
the waveguide assembly further comprises a plurality of discrete
agitating members in contact with and extending transversely
outward from the outer surface of the horn intermediate the inlet
port and the outlet port in longitudinally spaced relationship with
each other, the agitating members and the horn being constructed
and arranged for dynamic motion of the agitating members relative
to the horn upon ultrasonic vibration of the horn at said
predetermined frequency.
10. The ultrasonic treatment chamber set forth in claim 9 wherein
the agitating members are further configured to operate in an
ultrasonic cavitation mode of the agitating members corresponding
to the predetermined frequency and the liquid being treated in the
chamber.
11. The ultrasonic treatment chamber set forth in claim 1 wherein
the particles comprise at least one of alumina, aluminum, antimony,
bismuth, beryllium, cadmium, calcium, chromium, cobalt, copper,
iron, lead, nickel, platinum, rhodium, titanium, tungsten, zinc,
titanium dioxide, aluminum oxide, ceramic, mica and boron
nitride.
12. The ultrasonic treatment chamber set forth in claim 1 wherein
the predetermined frequency is in the range of about 20 kHz to
about 40 kHz.
13. The ultrasonic treatment chamber set forth in claim 9 wherein
the horn and agitating members together define a horn assembly of
the waveguide assembly, the horn assembly being disposed entirely
within the interior space of the housing.
14. The ultrasonic treatment chamber set forth in claim 1 further
comprising a mounting member for mounting the waveguide assembly on
the housing generally at one of said longitudinal ends thereof, the
mounting member being constructed to substantially vibrationally
isolate the housing from the waveguide assembly.
15. The ultrasonic treatment chamber set forth in claim 1 wherein
the horn has a length of approximately one-half wavelength.
16. The ultrasonic treatment chamber set forth in claim 7 wherein
the standing wave member is spaced from the terminal end of the
waveguide assembly a distance of approximately one-half
wavelength.
17. The ultrasonic treatment chamber set forth in claim 1 wherein
the housing further comprises a closure at one of said longitudinal
ends and having said outlet port therein, said closure having a
screen member intermediate the interior space of the housing and
the outlet port.
18. A process for ultrasonically treating a liquid in an ultrasonic
treatment chamber comprised of an elongate, generally tubular
housing having an interior space, an inlet and an outlet spaced
longitudinally from the inlet, the liquid having a thermal
conductivity, said process comprising: filling at least part of the
interior space of the housing with a bed of particles having a
thermal conductivity substantially greater than that of the liquid
whereby a ratio of the thermal conductivity of the particles to the
thermal conductivity of the liquid is in the range of about 2:1 to
about 400:1; directing the liquid into the housing at the housing
inlet for longitudinal flow within the housing through said bed of
particles to the housing outlet; generating mechanical ultrasonic
vibration within the housing in direct contact with the liquid
flowing therein as the liquid flows through said bed of
particles.
19. The process set forth in claim 18 further comprising the step
of generating a standing acoustic wave within the housing with the
standing acoustic wave having a node spaced longitudinally from the
housing outlet.
20. The process set forth in claim 18 wherein the ratio of the
thermal conductivity of said particles to the thermal conductivity
of said liquid is in the range of about 5:1 to about 400:1.
21. The process set forth in claim 18 wherein the ratio of the
thermal conductivity of said particles to the thermal conductivity
of said liquid is in the range of about 50:1 to about 400:1.
22. The process set forth in claim 18 wherein the particles have a
thermal conductivity of at least about 5 w/m-K.
23. The process set forth in claim 18 wherein the particles have a
thermal conductivity of at least about 30 w/m-K.
24. The process set forth in claim 18 wherein the particles have a
thermal conductivity of at least about 100 w/m-K.
25. The process set forth in claim 18 wherein the particles
comprise at least one of alumina, aluminum, antimony, bismuth,
beryllium, cadmium, calcium, chromium, cobalt, copper, iron, lead,
nickel, platinum, rhodium, titanium, tungsten, zinc, titanium
dioxide, aluminum oxide, ceramic, mica and boron nitride.
26. The process set forth in claim 18 wherein the step of
generating mechanical ultrasonic vibration comprises generating
mechanical ultrasonic vibration at a frequency in the range of
about 20 kHz to about 40 kHz.
Description
FIELD OF INVENTION
[0001] This invention relates generally to systems for
ultrasonically treating a liquid, more particularly for
ultrasonically treating a flowing liquid in a treatment chamber in
which particulate material is present in the chamber.
BACKGROUND
[0002] Liquid reaction or treatment chambers find numerous
applications for enhancing the treatment of liquids such as a
single component liquid, liquid-liquid reaction and/or mixing,
liquid-gas reaction and/or mixing and liquid-particulate material
reaction and/or mixing. For example, in formulating inks, paints
and other viscous materials two or more components (at least one
being a liquid) are mixed together in such a treatment chamber to
form the applicable solution. Other examples include the
simultaneous introduction of various liquids and gases into the
chamber to promote certain reactions. This would include the flow
of water into the chamber with the introduction of gases such as
air and/or oxygen and/or ozone only to mention a few. Also such
chambers can be used to induce a variety of chemical reactions such
as the decomposition of hydrogen peroxide, emulsion polymerization
reactions and the creation of emulsions for emulsion polymerization
mechanisms.
[0003] In other applications, treatment chambers can be used for
the deagglomeration of particles in a liquid stream. This would
include the deagglomeration of nano-particles such as pigments used
in the formulation of inks. Plus the simultaneous formulation of an
ink using these nano-pigment particles. This system can also have
the simultaneous exposure to UltraViolet (UV) light to promote
certain reactions of fluids or fluid/gas or fluid/gas/solids
systems in the ultrasonic chamber. Another application could be in
the medical field where a treatment chamber is used in the
preparation of pharmaceutical formulations that are composed of
powders/liquids and liquids for dispensing for use.
[0004] In many applications of reaction or treatment chambers, part
of the desired treatment is to subject the liquid flowing within
the chamber to substantial heat, such as to invoke a desired
reaction, be it a single liquid reaction, a liquid-liquid reaction,
a liquid-gas reaction or a liquid-solid (e.g., particle) reaction.
In other applications, it is often advantageous to provide the
chamber with some agitating mechanism by which liquid is agitated
within an elongate column or chamber. By agitating the liquid, a
desired reaction (e.g., mixing or other result) may be expedited
and thus capable of being achieved in a continuous flow operation.
As a result, treatment chambers that facilitate such agitation are
particularly useful in continuous flow treatment processes.
[0005] Agitation of a liquid may be referred to as static
agitation, in which agitation is caused by the particular flow
parameters (e.g., flow rate, pressure, etc.) of the one or more
liquid components through a column. Static agitation may also occur
by directing a flow of liquid past stationary agitating members,
such as a helical vane-type construction or other structures
disposed in the flow column or chamber that disrupt and thus
turbulate the flow of the liquid to be treated. Dynamic agitation
is brought about by moving, e.g., rotating, oscillating, vibrating,
etc. one or more agitating members (e.g., vanes, fan blades, etc.)
within the treatment chamber through which the liquid flows.
[0006] One particularly useful type of dynamic agitation of the
liquid results from ultrasonic cavitation, a more rigorous
agitation, in the liquid. Ultrasonic cavitation refers to the
formation, growth and implosive collapse of bubbles in liquid due
ultrasonic energization thereof. Such cavitation results from
pre-existing weak points in the liquid, such as gas-filled crevices
in suspended particulate matter or transient microbubbles from
prior cavitation events. As ultrasound passes through a liquid, the
expansion cycles exert negative pressure on the liquid, pulling the
molecules away from one another. Where the ultrasonic energy is
sufficiently intense, the expansion cycle creates cavities in the
liquid when the negative pressure exceeds the local tensile
strength of the liquid, which varies according to the type and
purity of liquid.
[0007] Small gas bubbles formed by the initial cavities grow upon
further absorption of the ultrasonic energy. Under the proper
conditions, these bubbles undergo a violent collapse, generating
very high pressures and temperatures. In some fields, such as what
is known as sonochemistry, chemical reactions take advantage of
these high pressures and temperatures brought on by cavitation.
However, the growth and violent collapse of the bubbles themselves
provides a desirably rigorous agitation of the liquid. Cavitation
that occurs at the interface between the ultrasonically energized
liquid and a solid surface is rather asymmetric and generates high
speed jets of liquid, further agitating the liquid. This type of
cavitation is particularly useful, for example, in facilitating a
more complete mixing together of two or more components of a liquid
solution.
[0008] It is known to pack some treatment chambers with a bed of
particles, such as in the manner of a fluidized bed reactor. The
particles are thus in the flow path of the liquid within the
treatment chamber and further facilitate treatment of the liquid.
However, where such particles are present in the chamber, the
chamber must be configured to prevent the particles from being
carried (or forced) out of the chamber by the liquid flowing
therein. For example, a screen element may block the outlet of the
chamber to block the particles, but not the liquid, from exiting
the chamber. While such a screen element can be effective, there is
a risk that the particles will agglomerate or otherwise build up on
the screen element and reduce the flow rate of the liquid out of
the chamber, thereby increasing the pressure in the chamber.
[0009] There is need, therefore, for a continuous flow ultrasonic
liquid treatment chamber that takes advantage of the benefits of
ultrasonic energy to treat a flowing liquid, particularly where
particles are used in such a treatment chamber, while maintaining
and achieving desired operational and environmental conditions of
the treatment chamber.
SUMMARY
[0010] In one embodiment, an ultrasonic treatment chamber for
ultrasonically treating a liquid having a thermal conductivity
generally comprises an elongate housing having longitudinally
opposite ends and an interior space. The housing is generally
closed at its longitudinal ends and has an inlet port for receiving
liquid into the interior space of the housing and an outlet port
through which liquid is exhausted from the housing following
ultrasonic treatment of the liquid. The outlet port is spaced
longitudinally from the inlet port such that liquid flows
longitudinally within the interior space of the housing from the
inlet port to the outlet port. An elongate ultrasonic waveguide
assembly extends longitudinally within the interior space of the
housing and is operable at a predetermined ultrasonic frequency to
ultrasonically energize liquid flowing within the housing. The
waveguide assembly comprises an elongate ultrasonic horn disposed
intermediate the inlet port and the outlet port of the housing and
having an outer surface located for contact with liquid flowing
within the housing from the inlet port to the outlet port. A bed of
particles is also disposed within the interior space of the housing
transversely intermediate the waveguide assembly and the chamber
housing. These particles have a thermal conductivity substantially
greater than that of the liquid flowing within the housing, such
that a ratio of the thermal conductivity of the particles to the
thermal conductivity of the liquid is in the range of about 2:1 to
about 400:1.
[0011] A process according to one embodiment for ultrasonically
treating a liquid in an ultrasonic treatment chamber generally
comprises filling at least part of an interior space of the chamber
housing with a bed of particles having a thermal conductivity
substantially greater than that of the liquid whereby a ratio of
the thermal conductivity of the particles to the thermal
conductivity of the liquid is in the range of about 2:1 to about
400:1. The liquid is directed into the housing at a housing inlet
for longitudinal flow within the housing through the bed of
particles to the housing outlet. Mechanical ultrasonic vibration is
generated within the housing in direct contact with the liquid
flowing within the housing as the liquid flows through the bed of
particles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic of a system according to one
embodiment of a system for ultrasonically treating a liquid;
[0013] FIG. 2 is a side elevation of an ultrasonic treatment
chamber of the system of FIG. 1, with a bed of particles omitted
from the treatment chamber;
[0014] FIG. 3 is a longitudinal (e.g., vertical) cross-section of
the ultrasonic treatment chamber of FIG. 2;
[0015] FIG. 3A is an enlarged, fragmented view of a portion of the
cross-section of FIG. 3;
[0016] FIG. 3B is a top plan view of a collar that forms part of
the housing of the ultrasonic treatment chamber of FIG. 2;
[0017] FIG. 4 is a front perspective of an alternative embodiment
of a horn assembly; and
[0018] FIG. 5 is a schematic cross-section of the ultrasonic
treatment chamber similar to that of FIG. 3 during operation
according to one embodiment of a process for ultrasonically
treating a liquid.
[0019] Corresponding reference characters indicate corresponding
parts throughout the drawings.
DETAILED DESCRIPTION
[0020] With reference now to the drawings, and in particular to
FIG. 1, in one embodiment a system for ultrasonically treating a
liquid generally comprises an ultrasonic treatment chamber,
generally indicated at 21, that is operable to ultrasonically treat
a liquid with both mechanical vibration and with a standing
acoustic wave. The term "liquid" as used herein is intended to
refer to a single component liquid, a solution comprised of two or
more components in which at least one of the components is a liquid
such as a liquid-liquid mixture, a liquid-gas mixture or a liquid
in which particulate matter is entrained, or other viscous
fluids.
[0021] The ultrasonic treatment chamber 21 is illustrated
schematically in the embodiment of FIG. 1 and described further
herein with reference to use of the treatment chamber generally in
the manner of a packed bed or fluidized bed reactor in which the
chamber is packed at least in part with particulate matter (broadly
referred to herein as chamber particles 24), typically spherically
shaped beads or particles, for treating liquid as the liquid passes
through the chamber. In the particular embodiment illustrated in
FIG. 1, a liquid treatment system 23 is configured to utilize the
ultrasonic treatment chamber 21 for mixing together two or more
components of a liquid solution.
[0022] For example, some contemplated mixing uses for the
ultrasonic treatment chamber 21 include, without limitation, mixing
resins and curing agents for the plastic industry; mixing pulp
slurries with chemical additives such as bleaching agents, wet
strength agents, starches, dyes, enzymes, fillers, anti-slime
agents, silicone additives, etc.; mixing compounds used in the
paper and tissue industries, such as clay slurries for coatings,
polymeric additives such as wet strength resins, starch
suspensions, silicone compounds, lotions, filler suspensions, etc.;
mixing resins and coloring agents, fillers, and other compounds;
mixing immiscible phases to prepare emulsions, such as food
emulsions (e.g., for sun block products, hand lotions, lipstick
compounds, etc.), cosmetics, cleaning agents (including
nanoemulsions of oil and water), pharmaceutical compounds, etc; and
mixing coloring agents and other compounds to form cosmetics such
as hair dyes; mixing pulp slurries with chemical additives such as
bleaching agents, wet strength agents, starches, dyes, etc.; and
mixing compounds used in the paper and tissue industries, such as
clay slurries.
[0023] It is understood, however, that the ultrasonic liquid
treatment chamber 21 may be used with liquid ultrasonic treatment
systems other than for mixing but where passing a liquid through a
bed of particulate material at least in part comprises the desired
treatment of the liquid. Non-limiting examples include food
processing and treatment; degassing solutions (e.g., pulling
dissolved gasses from liquid solutions such as oxygen, nitrogen,
ammonia, etc.); and enhancing chemical reactions, for example, as
is common in sonochemistry where excitation is imparted to a
chemical reaction to expedite the reaction.
[0024] Additional examples include degassing a mixture to simplify
subsequent treatment and reduce void formation; deinking recycled
papermaking fibers, in which ultrasonic energy may assist in
removal of inks (particularly in the presence of enzymes,
detergents, or other chemicals); hydrogenating oils, cheese, or
other food stuffs, in which gas and slurries or liquids must be
mixed; homogenizing milk and other compounds; treating wastewater
and/or manure, in which a variety of additives and air bubbles may
need to be mixed with a slurry; manufacturing petrochemicals such
as lubricant mixtures, gasoline blends, wax mixtures, etc., and
compounds derived from petrochemicals; processing dough (e.g.,
mixing combinations of agents to be added to flour or processing
the dough itself, which may result in improved breakdown of gluten,
etc.). The ultrasonic treatment chamber 21 may also be used in
chemical reactors involving single or multiple phases, including
slurries.
[0025] In other contemplated uses, the ultrasonic treatment chamber
21 may be used to remove entrapped gas bubbles from coating
solutions that are used in gravure coating, meyer rod coating or
any other coating applications where it is desirable to remove air
bubbles from a solution. The ultrasonic treatment chamber 21 may
also be used to remove liquid or solid material from a solution,
such as where the chamber particles comprise an adsorbent
material.
[0026] Additional benefits of the ultrasonic treatment chamber 21
the ability to control or more uniformly heat liquid as it passes
through the chamber. For example, the temperature can be controlled
by energy input and/or by throughput (e.g., flow rate) of the
liquid through the chamber 21. As a result, additional applications
are more readily conducted, such as gentle heating to aid
high-speed fermentation of a bioreactor (enzymes or microbes),
achieving higher temperature for high throughput pasteurization and
achieving even higher temperature sterilization processes and
reactions.
[0027] In particular, the ultrasonic treatment chamber 21 is
suitable for use in liquid treatment systems in which ultrasonic
treatment of the liquid is desired in an in-line, e.g., continuous
flow process in which fluid flows continuously through the chamber.
It is contemplated, though, that the treatment chamber 21 may be
used in a liquid treatment system in which liquid is treated in
accordance with a batch process instead of a continuous flow
process and remain with the scope of this invention.
[0028] In the illustrated embodiment of FIG. 1, the ultrasonic
treatment chamber 21 is generally elongate and has an inlet end 25
(a lower end in the orientation of the illustrated embodiment) and
an outlet end 27 (an upper end in the orientation of the
illustrated embodiment). The system 23 is configured such that
liquid enters the treatment chamber 21 generally at the inlet end
25 thereof, flows generally longitudinally within the chamber
(e.g., upward in the orientation of illustrated embodiment) and
exits the chamber generally at the outlet end of the chamber.
[0029] The terms "upper" and "lower" are used herein in accordance
with the vertical orientation of the ultrasonic treatment chamber
21 illustrated in the various drawings and are not intended to
describe a necessary orientation of the chamber in use. That is,
while the chamber 21 is most suitably oriented vertically, with the
outlet end 27 of the chamber above the inlet end 25 as illustrated
in the various drawings, it is understood that the chamber may be
oriented with the inlet end above the outlet end, or it may be
oriented other than in a vertical orientation and remain within the
scope of this invention.
[0030] The terms axial and longitudinal refer directionally herein
to the lengthwise direction of the chamber 21 (e.g., end-to-end
such as the vertical direction in the illustrated embodiments). The
terms transverse, lateral and radial refer herein to a direction
normal to the axial (e.g., longitudinal) direction. The terms inner
and outer are also used in reference to a direction transverse to
the axial direction of the ultrasonic treatment chamber 21, with
the term inner referring to a direction toward the interior of the
chamber (e.g., toward the longitudinal axis of the chamber) and the
term outer referring to a direction toward the exterior of the
chamber (e.g., away from the longitudinal axis of the chamber).
[0031] The inlet end 25 of the ultrasonic treatment chamber 21 is
in fluid communication with a suitable delivery system, generally
indicated at 29, that is operable to direct one or more liquid
components to, and more suitably through, the chamber 21. For
example, in the illustrated treatment system 23 of FIG. 1 the
delivery system 29 comprises a plurality of pumps 31 (such as one
pump for each component of the solution to be mixed in the chamber)
operable to pump the respective components from a corresponding
source (illustrated schematically in FIG. 1 as reference number 32)
thereof to the inlet end 25 of the chamber 21 via suitable conduits
(illustrated schematically in FIG. 1 as reference number 33). As an
example, four such pumps 31, component sources and corresponding
conduits 33 are shown in FIG. 1.
[0032] It is understood that the delivery system 29 may be
configured to deliver less than four (including one), or more than
four components to the treatment chamber 21 without departing from
the scope of this invention. It is also contemplated that delivery
systems other than that illustrated in FIG. 1 and described herein
may be used to deliver one or more components to the inlet end 25
of the ultrasonic treatment chamber 21 without departing from the
scope of this invention.
[0033] With reference now to FIG. 2, the ultrasonic treatment
chamber 21 of the liquid treatment system 23 comprises a housing 51
defining an interior space 53 of the chamber through which liquid
delivered to the chamber flows from the inlet end 25 to the outlet
end 27 thereof. The housing 51 suitably comprises an elongate tube
55 generally defining, at least in part, a sidewall 57 of the
chamber 21. In the illustrated embodiment, the housing 51 further
comprises an inlet collar 61 connected to and mounted on one end of
the tube 55 to define the inlet end 25 of the chamber 21.
[0034] The housing 51 also comprises a closure 63 connected to and
substantially closing the longitudinally opposite end of the
sidewall 57, and having at least one outlet port 65 (broadly, an
outlet) therein to generally define the outlet end 27 of the
treatment chamber 21. The closure 63 also has a screen element 66
held in assembly therewith and blocking the outlet port 65 (e.g.,
between the outlet port and the interior space 53 of the chamber
21) to inhibit the chamber particles 24 from flowing out of the
chamber through the outlet port along with the liquid solution. The
sidewall 57 (e.g., defined by the elongate tube 55) of the chamber
21 has an inner surface 67 that together with the collar 61 and the
closure 63 define the interior space 53 of the chamber.
[0035] In the illustrated embodiment, the tube 55 is generally
cylindrical so that the chamber sidewall 57 is generally annular in
cross-section. However, it is contemplated that the cross-section
of the chamber sidewall 57 may be other than annular, such as
polygonal or another suitable shape, and remain within the scope of
this invention. The chamber sidewall 57 of the illustrated chamber
21 is suitably constructed of a transparent material, although it
is understood that any suitable material may be used as long as the
material is compatible with the liquid components being treated in
the chamber, the pressure at which the chamber is intended to
operate, and other environmental conditions within the chamber such
as temperature.
[0036] With particular reference to FIG. 3B, the inlet collar 61 at
the inlet end 25 of the chamber 21 is generally annular and has at
least one, and more suitably a plurality of inlet ports 69a, 69b
(broadly, an inlet) formed therein for receiving liquid solution
components into the interior space 53 of the chamber 21. At least
one inlet port 69a is oriented generally tangentially relative to
the annular collar 61 so that liquid flows into the interior space
53 of the chamber 21 generally tangentially thereto to impart a
swirling action to liquid as it enters the chamber. More suitably,
in the illustrated embodiment a pair of inlet ports 69a, 69b are
arranged in parallel alignment with each and extend generally
tangentially relative to the annular collar 61, with one port 69a
being designated herein as the outer inlet port and the other port
69b being designated the inner inlet port.
[0037] This dual tangential inlet port 69a, 69b arrangement is
particularly useful for initiating mixing of two or more components
together before the liquid solution is further subjected to
ultrasonic treatment within the chamber 21. In a particularly
suitable use of this arrangement, where the liquid to be treated in
the chamber 21 comprises two or more liquids, the liquid having the
lowest viscosity is directed to flow into the chamber via the outer
inlet port 69a while the liquid having the highest viscosity is
directed to flow into the chamber via the inner inlet port 69b. The
flow of the lower viscosity ingredient through the outer inlet port
69a has a tendency to draw the higher viscosity ingredient into the
interior space 53 of the chamber 21 to speed the rate at which the
higher viscosity ingredient is introduced into the chamber.
[0038] This action, combined with the swirling action resulting
from the tangential direction in which the liquid components are
directed into the chamber 21, facilitate an initial mixing of these
two components before the liquid solution flows further through the
chamber for ultrasonic treatment. In the illustrated embodiment,
the collar 61 also has an additional tangential set of inlet ports
69a, 69b and a pair of generally vertically oriented inlet ports
71. It is understood, however, that none of the ports 69a, 69b need
to be oriented tangentially relative to the collar 61 to remain
within the scope of this invention. It is also understood that the
number of inlet ports 69a, 69b, 71 may vary, and may even be
limited to a single inlet port.
[0039] An ultrasonic waveguide assembly, generally indicated at
101, extends longitudinally at least in part within the interior
space 53 of the chamber 21 to ultrasonically energize liquid (and
any other components of the liquid solution) flowing through the
interior space 53 of the chamber, as well to ultrasonically
energize the chamber particles 24. In particular, the ultrasonic
waveguide assembly 101 of the illustrated embodiment extends
longitudinally from the lower or inlet end 25 of the chamber 21 up
into the interior space 53 thereof to a terminal end 103 of the
waveguide assembly disposed intermediate the inlet ports 69a, 69b
and the outlet port 65. More suitably, the waveguide assembly 101
is mounted, either directly or indirectly, to the chamber housing
51 as will be described later herein.
[0040] The ultrasonic waveguide assembly 101 suitably comprises an
elongate horn assembly, generally indicated at 105, disposed
entirely with the interior space 53 of the housing 51 intermediate
the uppermost inlet port and the outlet port for complete
submersion within the liquid being treated within the chamber 21,
and more suitably it is aligned coaxially with the chamber sidewall
57. The horn assembly 105 has an outer surface 107 that together
with the inner surface 67 of the sidewall 57 defines a flow path
within the interior space 53 of the chamber 21 along which liquid
and other components flow past the horn assembly within the chamber
(this portion of the flow path being broadly referred to herein as
the ultrasonic treatment zone). The horn assembly 105 has an upper
end 109 defining a terminal end of the horn assembly (and therefore
the terminal end 103 of the waveguide assembly) and a
longitudinally opposite lower end 111. The waveguide assembly 101
of the illustrated embodiment also comprises a booster 113
coaxially aligned with and connected at an upper end thereof to the
lower end 111 of the horn assembly 105. It is understood, however,
that the waveguide assembly 101 may comprise only the horn assembly
105 and remain within the scope of this invention. It is also
contemplated that the booster 113 may be disposed entirely exterior
of the chamber housing 51, with the horn assembly 105 mounted on
the chamber housing 51 without departing from the scope of this
invention.
[0041] The ultrasonic waveguide assembly 101, and more particularly
the booster 113 in the illustrated embodiment of FIG. 3, is
suitably mounted on the chamber housing 51, e.g., on the tube 55
defining the chamber sidewall 57, at the upper end thereof by a
mounting member 115 that is configured to vibrationally isolate the
waveguide assembly (which vibrates ultrasonically during operation
thereof) from the ultrasonic treatment chamber housing. That is,
the mounting member 115 inhibits the transfer of longitudinal and
transverse mechanical vibration of the waveguide assembly 101 to
the chamber housing 51 while maintaining the desired transverse
position of the waveguide assembly (and in particular the horn
assembly 105) within the interior space 53 of the chamber housing
and allowing both longitudinal and transverse displacement of the
horn assembly within the chamber housing. In the illustrated
embodiment, the mounting member 115 also at least in part (e.g.,
along with the booster 113) closes the inlet end 25 of the chamber
21.
[0042] As one example, the mounting member 115 of the illustrated
embodiment generally comprises an annular outer segment 117
extending transverse to the waveguide assembly 101 in transversely
spaced relationship therewith, and a flange member 119
interconnecting the outer segment to the waveguide assembly. While
the flange member 119 and transverse outer segment 117 of the
mounting member 115 extend continuously about the circumference of
the waveguide assembly 101, it is understood that one or more of
these elements may be discontinuous about the waveguide assembly
such as in the manner of wheel spokes, without departing from the
scope of this invention. The outer segment 117 of the mounting
member 115 is particularly configured to seat down against a
shoulder 121 formed by the inlet collar 61.
[0043] As seen best in FIG. 3A, the internal cross-sectional
dimension (e.g., internal diameter) of the collar 61 is stepped
outward as the collar extends longitudinally downward away from the
chamber sidewall 57 to accommodate the flange member 119. In one
particularly suitable embodiment, the collar 61 is sufficiently
sized to be transversely spaced from the flange member 119 to
define a generally annular gap 123 therebetween in which liquid
delivered to the chamber 21 via the inlet ports 69a, 69b of the
collar enters the interior space 53 of the chamber. This annular
gap 123 further facilitates the swirling action of the liquid upon
entry into the chamber 21 via the collar inlet ports 69a, 69b.
[0044] The mounting member 115 is suitably sized in transverse
cross-section so that at least an outer edge margin of the outer
segment 117, and more suitably a substantial transverse portion of
the outer segment is seated on the shoulder 121 formed on the
collar 61. A suitable fastening system (not shown), such as a
plurality of bolts and corresponding nuts (not shown), secures the
outer segment 117 of the mounting member 115 to the shoulder 121
formed by the collar 61 to thereby connect the booster 113 (and
more broadly the waveguide assembly 101) to the chamber housing
51.
[0045] The flange member 119 may suitably be constructed relatively
thinner than the outer segment 117 of the mounting member 115 to
facilitate flexing and/or bending of the flange member 119 in
response to ultrasonic vibration of the waveguide assembly 101. As
an example, in one embodiment the thickness of the flange member
119 may be in the range of about 0.2 mm to about 5 mm, and more
suitably about 2.5 mm. The flange member 119 of the illustrated
mounting member 115 suitably has an inner transverse component 125
connected to the waveguide assembly 101 and extending generally
transversely outward therefrom but inward of the outer segment 117
of the mounting member, and an axial, or longitudinal component 127
interconnecting the transverse inner component with the outer
segment of the mounting member and together with the transverse
inner component generally forming a generally L-shaped
cross-section of the flange member 119. It is contemplated,
however, that the flange member 119 may instead have a generally
U-shaped cross-section or other suitable cross-sectional shape such
as an H-shape, an I-shape, an inverted U-shape and the like and
remain within the scope of this invention. Additional examples of
suitable mounting member 115 configurations are illustrated and
described in U.S. Pat. No. 6,676,003, the entire disclosure of
which is incorporated herein by reference to the extent it is
consistent herewith.
[0046] The longitudinal component 127 of the illustrated flange
member 119 is suitably cantilevered to the transverse outer segment
117 and to the transverse inner component 125 of the flange member,
while the inner component of the flange member is cantilevered to
the waveguide assembly 101. Accordingly, the flange member 119 is
capable of dynamically bending and/or flexing relative to the outer
segment 117 of the mounting member 115 in response to vibratory
displacement of the waveguide assembly 101 to thereby isolate the
chamber housing 51 from transverse and longitudinal displacement of
the waveguide assembly.
[0047] While in the illustrated embodiment the transverse outer
segment 117 of the mounting member 115 and the transverse inner
component 125 of the flange member 119 are disposed generally at
longitudinally offset locations relative to each other, it is
understood that they may be disposed at generally the same location
(e.g., where the flange member is generally U-shaped in
cross-section) or at locations other than those illustrated in FIG.
3) without departing from the scope of this invention.
[0048] In one particularly suitable embodiment the mounting member
115 is of single piece construction. Even more suitably the
mounting member 115 may be formed integrally with the booster 113
(and more broadly with the waveguide assembly 101) as illustrated
in FIG. 3. However, it is understood that the mounting member 115
may be constructed separate from the waveguide assembly 101 and
remain within the scope of this invention. It is also understood
that one or more components of the mounting member 115 may be
separately constructed and suitably connected or otherwise
assembled together.
[0049] In one suitable embodiment the mounting member 115 is
further constructed to be generally rigid (e.g., resistant to
static displacement under load) so as to hold the waveguide
assembly 101 in proper alignment within the interior space 53 of
the chamber 21. For example, the rigid mounting member 115 in one
embodiment may be constructed of a non-elastomeric material, more
suitably metal, and even more suitably the same metal from which
the booster 113 (and more broadly the waveguide assembly 101) is
constructed. The term rigid is not, however, intended to mean that
the mounting member 115 is incapable of dynamic flexing and/or
bending in response to ultrasonic vibration of the waveguide
assembly 101. In other embodiments, the rigid mounting member 115
may be constructed of an elastomeric material that is sufficiently
resistant to static displacement under load but is otherwise
capable of dynamic flexing and/or bending in response to ultrasonic
vibration of the waveguide assembly 101. While the mounting member
115 illustrated in FIG. 3 is constructed of a metal, and more
suitably constructed of the same material as the booster 113, it is
contemplated that the mounting member may be constructed of other
suitable generally rigid materials without departing from the scope
of this invention.
[0050] A suitable ultrasonic drive system 131 (shown schematically
in FIG. 1) including at least an exciter (not shown) and a power
source (not shown) is disposed exterior of the chamber 21 and
operatively connected to the booster 113 (and more broadly to the
waveguide assembly 101) to energize the waveguide assembly to
mechanically vibrate ultrasonically. Examples of suitable
ultrasonic drive systems 131 include a Model 20A3000 system
available from Dukane Ultrasonics of St. Charles, Ill., and a Model
2000CS system available from Herrmann Ultrasonics of Schaumberg,
Ill.
[0051] The drive system 131 is suitably capable of operating the
waveguide assembly 101 at a frequency in the range of about 15 kHz
to about 100 kHz, more suitably in the range of about 15 kHz to
about 60 kHz, and even more suitably in the range of about 20 kHz
to about 40 kHz. Such ultrasonic drive systems 131 are well known
to those skilled in the art and need not be further described
herein.
[0052] With particular reference to FIG. 3, the horn assembly 105
comprises an elongate, generally cylindrical horn 133 having an
outer surface 135, and two or more (i.e., a plurality of) agitating
members 137 connected to the horn and extending at least in part
transversely outward from the outer surface of the horn in
longitudinally spaced relationship with each other. The horn 133 is
suitably sized to have a length equal to about one-half of the
resonating wavelength (otherwise commonly referred to as one-half
wavelength) of the horn. In one particular embodiment, the horn 133
is suitably configured to resonate in the ultrasonic frequency
ranges recited previously, and most suitably at 20 kHz. For
example, the horn 133 may be suitably constructed of a titanium
alloy (e.g., Ti6Al4V) and sized to resonate at 20 kHz. The one-half
wavelength horn 133 operating at such frequencies thus has a length
(corresponding to a one-half wavelength) in the range of about 4
inches to about 6 inches, more suitably in the range of about 4.5
inches to about 5.5 inches, even more suitably in the range of
about 5.0 inches to about 5.5 inches, and most suitably a length of
about 5.25 inches (133.4 mm). It is understood, however, that the
ultrasonic treatment chamber 21 may include a horn assembly 105 in
which the horn 133 is sized to have any increment of one-half
wavelength without departing from the scope of this invention.
[0053] In the illustrated embodiment, the agitating members 137
comprise a series of six washer-shaped rings that extend
continuously about the circumference of the horn member 133 in
longitudinally spaced relationship with each other and transversely
(e.g., radially in the illustrated embodiment) outward from the
outer surface of the horn. In this manner the vibrational
displacement of each of the agitating members 137 relative to the
horn 133 is relatively uniform about the circumference of the horn.
It is understood, however, that the agitating members 137 need not
each be continuous about the circumference of the horn 133. For
example, the agitating members 137 may instead be in the form of
spokes, blades, fins or other discrete structural members that
extend transversely outward from the outer surface 135 of the horn
133.
[0054] To provide a dimensional example, for the horn 133 of the
illustrated embodiment of FIG. 3 having a length of about 5.25
inches (133.4 mm), one of the rings 137 is suitably disposed
adjacent the terminal end of the horn 133 (and hence of the
waveguide assembly 101), and more suitably is longitudinally spaced
approximately 0.063 inches (1.6 mm) from the terminal end of the
horn member. In other embodiments the uppermost ring 137 may be
disposed at the terminal end of the horn and remain within the
scope of this invention. The rings 137 are each about 0.125 inches
(3.2 mm) in thickness and are longitudinally spaced from each other
(between facing surfaces of the rings) a distance of about 0.875
inches (22.2 mm).
[0055] It is understood that the number of agitating members 137
(e.g., the rings in the illustrated embodiment) may be less than or
more than six without departing from the scope of this invention.
It is also contemplated that in other embodiments the agitating
members 137 may be omitted entirely without departing from the
scope of this invention, the horn outer surface 135 providing the
sole mechanical ultrasonic vibration contact with the liquid in the
flow path within the treatment chamber 21. It is further understood
that the longitudinal spacing between the agitating members 137 may
be other than as illustrated in FIG. 3 and described above (e.g.,
either closer or spaced further apart). While the rings 137
illustrated in FIG. 3 are equally longitudinally spaced from each
other, it is alternatively contemplated that where more than two
agitating members are present the spacing between longitudinally
consecutive agitating members need not be uniform to remain within
the scope of this invention.
[0056] In particular, the locations of the agitating members 137
are at least in part a function of the intended vibratory
displacement of the agitating members upon vibration of the horn
133. For example, in the illustrated embodiment the horn 133 has a
nodal region located generally longitudinally centrally of the horn
(e.g., between the third and fourth rings). As used herein, the
"nodal region" of the horn 133 refers to a longitudinal region or
segment of the horn member along which little (or no) longitudinal
displacement occurs during ultrasonic vibration of the horn and
transverse (e.g., radial in the illustrated embodiment)
displacement of the horn is generally maximized. Transverse
displacement of the horn 133 suitably comprises transverse
expansion of the horn but may also include transverse movement
(e.g., bending) of the horn.
[0057] In the illustrated embodiment, the configuration of the
one-half wavelength horn 133 is such that the nodal region is
particularly defined by a nodal plane (i.e., a plane transverse to
the horn member at which no longitudinal displacement occurs while
transverse displacement is generally maximized). This plane is also
sometimes referred to as a nodal point. Accordingly, agitating
members 137 (e.g., in the illustrated embodiment, the rings) that
are disposed longitudinally further from the nodal region of the
horn 133 will experience primarily longitudinal displacement while
agitating members that are longitudinally nearer to the nodal
region will experience an increased amount of transverse
displacement and a decreased amount of longitudinal displacement
relative to the longitudinally distal agitating members.
[0058] It is understood that the horn 133 may be configured so that
the nodal region is other than centrally located longitudinally on
the horn member without departing from the scope of this invention.
It is also understood that one or more of the agitating members 137
may be longitudinally located on the horn so as to experience both
longitudinal and transverse displacement relative to the horn upon
ultrasonic vibration of the horn assembly 105.
[0059] Still referring to FIG. 3, the agitating members 137 are
sufficiently constructed (e.g., in material and/or dimension such
as thickness and transverse length, which is the distance that the
agitating member extends transversely outward from the outer
surface 135 of the horn 133) to facilitate dynamic motion, and in
particular dynamic flexing/bending of the agitating members in
response to the ultrasonic vibration of the horn member. In one
particularly suitable embodiment, for a given ultrasonic frequency
at which the waveguide assembly 101 is to be operated in the
ultrasonic chamber (otherwise referred to herein as the
predetermined frequency of the waveguide assembly) and a particular
liquid to be treated within the chamber 21, the agitating members
137 and horn 133 are suitably constructed and arranged to operate
the agitating members in what is referred to herein as an
ultrasonic cavitation mode at the predetermined frequency.
[0060] As used herein, the ultrasonic cavitation mode of the
agitating members refers to the vibrational displacement of the
agitating members sufficient to result in cavitation (i.e., the
formation, growth, and implosive collapse of bubbles in a liquid)
of the liquid being treated at the predetermined ultrasonic
frequency. For example, where the liquid flowing within the chamber
comprises an aqueous solution, and more particularly water, and the
ultrasonic frequency at which the waveguide assembly 101 is to be
operated (i.e., the predetermined frequency) is about 20 kHZ, one
or more of the agitating members 137 are suitably constructed to
provide a vibrational displacement of at least 1.75 mils (i.e.,
0.00175 inches, or 0.044 mm) to establish a cavitation mode of the
agitating members. It is understood that the waveguide assembly 101
may be configured differently (e.g., in material, size, etc.) to
achieve a desired cavitation mode associated with the particular
liquid being treated. For example, as the viscosity of the liquid
being treated changes, the cavitation mode of the agitating members
may need to be changed.
[0061] In particularly suitable embodiments, the cavitation mode of
the agitating members corresponds to a resonant mode of the
agitating members whereby vibrational displacement of the agitating
members is amplified relative to the displacement of the horn.
However, it is understood that cavitation may occur without the
agitating members operating in their resonant mode, or even at a
vibrational displacement that is greater than the displacement of
the horn, without departing from the scope of this invention.
[0062] In one suitable dimensional example, a ratio of the
transverse length of at least one and more suitably all of the
agitating members 137 to the thickness of the agitating member is
in the range of about 2:1 to about 6:1. As another example, the
rings 137 illustrated in FIG. 3 each extend transversely outward
from the outer surface 135 of the horn 133 a length of about 0.5
inches (12.7 mm) and the thickness of each ring is about 0.125
inches (3.2 mm), so that the ratio of transverse length to
thickness of each ring is about 4:1. It is understood, however that
the thickness and/or the transverse length of the agitating members
137 may be other than that of the rings illustrated in FIG. 3
without departing from the scope of this invention. Also, while the
agitating members 137 (rings) of the illustrated embodiment each
have the same transverse length and thickness, it is understood
that the agitating members may have different thicknesses and/or
transverse lengths.
[0063] In the illustrated embodiment, the transverse length of the
agitating member 137 also at least in part defines the size (and at
least in part the direction) of the flow path along which liquid or
other flowable components in the interior space 53 of the chamber
21 flows past the horn assembly 105. For example, the horn 133
illustrated in FIG. 3 has a radius of about 0.875 inches (22.2 mm)
and the transverse length of each ring 137 is, as discussed above,
about 0.5 inches (12.7 mm). The radius of the inner surface 67 of
the housing sidewall 57 is approximately 1.75 inches (44.5 mm) so
that the transverse spacing between each ring and the inner surface
of the housing sidewall is about 0.375 inches (9.5 mm). It is
contemplated that the spacing between the horn outer surface 135
and the inner surface 67 of the chamber sidewall 57 and/or between
the agitating members 137 and the inner surface of the chamber
sidewall may be greater or less than described above without
departing from the scope of this invention.
[0064] In general, the horn 133 may be constructed of a metal
having suitable acoustical and mechanical properties. Examples of
suitable metals for construction of the horn 133 include, without
limitation, aluminum, monel, titanium, stainless steel, and some
alloy steels. It is also contemplated that all or part of the horn
133 may be coated with another metal such as silver, platinum and
copper to mention a few. In one particularly suitable embodiment,
the agitating members 137 are constructed of the same material as
the horn 133, and are more suitably formed integrally with the
horn. In other embodiments, one or more of the agitating members
137 may instead be formed separate from the horn 133 and connected
thereto to form the horn assembly 105.
[0065] While the agitating members 137 (e.g., the rings)
illustrated in FIG. 3 are relatively flat, i.e., relatively
rectangular in cross-section, it is understood that the rings may
have a cross-section that is other than rectangular without
departing from the scope of this invention. The term cross-section
is used in this instance to refer to a cross-section taken along
one transverse direction (e.g., radially in the illustrated
embodiment) relative to the horn outer surface 135). Additionally,
although the agitating members 137 (e.g., the rings) illustrated in
FIG. 3 are constructed only to have a transverse component, it is
contemplated that one or more of the agitating members may have at
least one longitudinal (e.g., axial) component to take advantage of
transverse vibrational displacement of the horn (e.g., at and near
the nodal region of the horn illustrated in FIG. 3) during
ultrasonic vibration of the waveguide assembly 101.
[0066] For example, FIG. 4 illustrates one alternative embodiment
of a horn assembly 205 having five agitating members 237 extending
transversely outward from the outer surface 235 of the horn 233.
While each of the agitating members 237 has a transverse component,
e.g., in the form of a ring similar to those of FIG. 3, the
centermost agitating member 237 also has an annular longitudinal
component 241 secured to the transverse component. In particular,
the centermost agitating member 237 is disposed longitudinally
generally at the nodal region, and more particularly at the nodal
plane of the horn 233 in the illustrated embodiment of FIG. 4,
where the transverse displacement of the horn 233 is generally
maximized during ultrasonic energization thereof while longitudinal
displacement is generally minimized. The longitudinal component 241
is thus capable of dynamic motion (e.g., flexing/bending) in a
transverse direction in response to transverse displacement of the
horn 233 upon ultrasonic energization of the horn.
[0067] It is contemplated that the longitudinal component 241 need
not extend entirely longitudinal, i.e., parallel to the outer
surface of the horn 233, as long as the longitudinal component has
some longitudinal vector to it. Also, while in the illustrated
embodiment the agitating member 237 having the longitudinal
component 241 is generally T-shaped in cross-section, it is
understood that other configurations of such an agitating member
are suitable, such as an L-shaped cross-section (with the
longitudinal component extending either up or down), a plus-shaped
cross-section, or other suitable cross-section. It is also
contemplated that one or more holes may formed in the centermost
agitating member 237, such as in the transverse component and/or
the longitudinal components 241 to allow fluid to flow freely in
both the horizontal and vertical direction through this member.
[0068] As best illustrated in FIG. 3, the terminal end 103 of the
waveguide assembly 101 (e.g., the end 109 of the horn 133 in the
illustrated embodiment) is substantially spaced longitudinally from
the outlet port 65 (broadly, the outlet) at the outlet end 27 of
the chamber 21 to provide what is referred to herein as a buffer
zone (i.e., the portion of the interior space 53 of the chamber
housing 51 longitudinally beyond the terminal end 103 of the
waveguide assembly 101) to allow a more uniform mixing or flow as
liquid flows downstream of the terminal end 103 of the waveguide
assembly 101 to the outlet end 27 of the chamber. For example, in
one suitable embodiment the buffer zone has a void volume (i.e.,
the volume of that portion of the open space 53 within the chamber
housing 51 within the buffer zone) in which the ratio of this
buffer zone void volume to the void volume of the remainder of the
chamber housing interior space upstream of the terminal end of the
waveguide assembly is suitably in the range of about 0.01:1 to
about 5.0:1, and more suitably about 1:1.
[0069] Providing the illustrated buffer zone is particularly useful
where the chamber 21 is used for mixing two or more components
together to form a liquid solution such as in the system 23 of FIG.
1. That is, the longitudinal spacing between the terminal end 103
of the waveguide assembly 101 and the outlet port 65 of the chamber
21 provides sufficient space for the agitated flow of the mixed
liquid solution to generally settle prior to the liquid solution
exiting the chamber via the outlet port. This is particularly
useful where, as in the illustrated embodiment, one of the
agitating members 137 is disposed at or adjacent the terminal end
of the horn 133. While such an arrangement leads to beneficial
back-mixing of the liquid as it flows past the terminal end of the
horn 133, it is desirable that this agitated flow settle out at
least in part before exiting the chamber. It is understood,
however, that the terminal end 103 of the waveguide assembly 101
within the interior space 53 of the chamber 21 may be disposed
longitudinally nearer to the outlet port 65 at the outlet end 27 of
the chamber, or that the buffer zone may even be substantially
entirely omitted, without departing from the scope of this
invention.
[0070] The opposite, e.g., more proximal end of the horn assembly
105 is suitably spaced longitudinally from the collar 61 to define
what is referred to herein as a liquid intake zone in which initial
swirling of liquid within the interior space 53 of the chamber
housing 51 occurs upstream of the horn assembly 105. This intake
zone is particularly useful where the treatment chamber 21 is used
for mixing two or more components together whereby initial mixing
is facilitated by the swirling action in the intake zone as the
components to be mixed enter the chamber housing 51. It is
understood, though, that the proximal end of the horn assembly 105
may be nearer to the collar 61 than is illustrated in FIG. 3, and
may be substantially adjacent to the collar so as to generally omit
the intake zone, without departing from the scope of this
invention.
[0071] The illustrated ultrasonic treatment chamber 21 further
comprises a standing wave member, generally indicated at 301, in
the form of a reflector. The "standing wave member" is intended to
refer to a member other than the waveguide assembly 101 that
together with the waveguide assembly generates a standing wave
therebetween within the chamber housing 51. The reflector 301 is
disposed within the interior space 53 of the chamber 21 and more
particularly in the buffer zone between the terminal end 103 of the
waveguide assembly 101 and the outlet port 65 of the chamber 21 in
longitudinally spaced, opposed relationship with the terminal end
of waveguide assembly. The location of the reflector 301 in the
chamber 21 is also such that the reflector is spaced longitudinally
from (e.g., below in the illustrated embodiment) the outlet port 65
and more suitably the screen element 66 of the closure 63. Upon
ultrasonic operation of the waveguide assembly 101, the reflector
301 acts in conjunction with the waveguide assembly (which acts in
this instance as an ultrasonic transducer) to produce a standing
acoustic wave within the buffer zone, and more particularly between
the terminal end 103 of the waveguide assembly and the
reflector.
[0072] It is contemplated that instead of the reflector 301, the
standing wave member may be another wave generator, such as a
transducer spaced from the waveguide assembly in opposed
relationship therewith and operable to generate ultrasonic acoustic
wave energy that travels in a direction opposite the wave energy
generated by the waveguide assembly to together with the waveguide
assembly produce a standing acoustic wave therebetween.
[0073] In a particularly suitable embodiment the reflector 301
(broadly, the standing wave member) and waveguide assembly 101
produce a standing acoustic wave therebetween that has at least one
node, and which has no node at or adjacent the outlet port 65 and
more suitably at or adjacent the screen element 65. That is, any
node of the standing wave is spaced longitudinally from at least
the outlet port 65 and more suitably from the screen element 66 of
the closure 63. For example, the longitudinal spacing between the
terminal end 103 of the waveguide assembly 101 and the reflector
301 suitably corresponds to one-half of an acoustic wavelength
.lamda. (i.e., a one-half wavelength) wherein the wavelength
.lamda. of the standing wave is a function of the liquid flowing
within the buffer zone in the chamber 21 and the frequency at which
the waveguide assembly (acting as a transducer) is operated. In
particular,
.lamda.=c/f
[0074] where;
[0075] c=the speed of sound through the liquid in the chamber 21,
and
[0076] f=the operating frequency of the waveguide assembly 101.
[0077] In the illustrated embodiment, the position of the reflector
301 is suitably adjustable longitudinally relative to the terminal
end 103 of the waveguide assembly 101 to adjust the longitudinal
spacing between the reflector and the waveguide assembly. This
allows the reflector 301 to be selectively positioned relative to
the waveguide assembly 101, depending on the liquid solution being
treated and/or the predetermined operating frequency of the
waveguide assembly, so as to generate a one-half wavelength
standing wave (or a multiple of a one-half wavelength standing
wave). In particular, a support frame 303 comprised of two or more
support posts 305 extends through the closure 63 down into the
interior space 53 of the chamber 21, e.g., past the outlet port 65
and more suitably past the screen element 66 of the closure and is
adjustably moveable longitudinally relative to the closure. The
reflector 301 is suitably secured to the support frame 303 for
conjoint movement with the support frame relative to the closure 63
and waveguide assembly 101. The support frame 303 may be manually
adjustable or mechanically adjustable by a suitable adjustment
mechanism (not shown).
[0078] The reflector 301 of the illustrated embodiment comprises a
generally circular solid plate sized for sufficiently spaced
relationship with the chamber sidewall 57 so that the reflector
does not substantially reduce the flow rate of liquid through the
screen element 66 and outlet port 65. The reflector 301 is suitably
constructed from a material that has an acoustic impedance greater
than that of the liquid flowing within the chamber 21 (e.g., the
liquid in which the standing wave is generated), and more suitably
substantially greater. For example, in one embodiment the reflector
301 may be constructed from stainless steel. It is understood,
however, however that the reflector 301 may be constructed from any
suitable material having an impedance greater than that of the
liquid in the chamber 21 and remain within the scope of this
invention. It is also contemplated that the reflector 301 may be
other than plate-shaped and/or other than circular without
departing from the scope of this invention.
[0079] As illustrated in FIG. 3, the chamber particles 24 are
suitably disposed within the interior space 53 of the chamber 21 to
a level below (i.e., upstream from) the reflector 301, and more
suitably below (or upstream from) the terminal end 103 of the
waveguide assembly 101 so that the particles are not initially
(e.g., prior to liquid flow through the chamber) disposed within
the buffer zone. While the chamber particles 24 are most suitably
spherical in shape, it is contemplated that the particles may be of
any shape without departing from the scope of this invention.
[0080] In one particularly suitable embodiment, the chamber
particles 24 suitably have a relatively high thermal conductivity,
i.e., a thermal conductivity that is substantially greater than the
liquid being treated within the ultrasonic treatment chamber 21. As
an example, water has a thermal conductivity of about 0.60
watts/meter-.degree. Kelvin (hereafter indicated as w/m-K). As used
herein the term "thermal conductivity" refers to the ability of a
material to transmit or conduct heat. Thus, a higher thermal
conductivity indicates that such a material will more readily
(e.g., more rapidly) conduct heat.
[0081] In particularly suitable embodiments, a ratio of the thermal
conductivity of the relatively higher thermal conductivity
particles to the thermal conductivity of the liquid flowing in the
chamber (e.g., through the bed of particles) is in the range of
about 2:1 to about 400:1, more suitably in the range of about 5:1
to about 400:1, even more suitably in the range of about 10:1 to
about 400:1, still more suitably in the range of about 50:1 to
about 400:1, and may be in the range of about 100:1 to about 400:1.
In other embodiments, the thermally conductive chamber particles
have a thermal conductivity of at least about 1.0 w/m-K and still
more suitably at least about 5 w/m-K. In other embodiments, the
thermal conductivity of the chamber particles may be at least about
30, and may even be 100, 200 or more.
[0082] Examples of suitable materials from which the chamber
particles may be comprised so as to have a suitable thermal
conductivity (with the approximate thermal conductivity of the
identified material being provided in parenthesis following each,
the units being w/m-K) include, without limitation, alumina
(including corundum) (30), aluminum (237), antimony (24), bismuth
(8), beryllium (201), cadmium (97), calcium (125), chromium (94),
cobalt (100), copper (401), iron (80), lead (35), nickel (91),
platinum (72), rhodium (150), titanium (22), tungsten (173), zinc
(116), titanium dioxide (rutile, titania) (10), silicon carbide
(35-40), ceramic (110), mica (up to about 7) and boron nitride
(carborundum) (20).
[0083] Examples of other suitable materials from which the chamber
particles 24 may be made, such as comprised entirely of, partially
of or at least in part surface treated with, include, without
limitation, various mixed valent oxides, such as magnetite, nickel
oxide and the like; carbon and graphite; sulfide semiconductors,
such as FeS.sub.2 and CuFeS.sub.2; various hydrated salts and other
salts, such as calcium chloride dihydrate; polymers and copolymers
of polylactic acid which have metal ions such as iron, nickel for
example on the carboxylic acid portion of the polymer or chelated
with metal ions; aluminum hydroxide, zinc oxide and barium
titanate.
[0084] As one example of suitable particles, co-pending U.S.
application Ser. No. 11/530,210, entitled DELIVERY SYSTEMS FOR
DELIVERING FUNCTIONAL COMPOUNDS TO SUBSTRATES AND PROCESSES OF
USING THE SAME and filed Sep. 8, 2006, the entire disclosure of
which is incorporated herein by reference, discloses the use of
adsorbent particles comprised of alumina to remove desired
materials from the liquid flowing through the treatment chamber
21.
[0085] In particularly suitable embodiments, the chamber particles
are sized in the range of about 5 nanometers to about 500 microns,
and more suitably about 10 nanometers to about 1 micron. It is
understood, however, that the chamber particles 24 may be sized
smaller or larger than the above ranges without departing from the
scope of this invention.
[0086] In operation of the liquid treatment system 23 illustrated
in FIG. 1, the one or more components 32 (with at least one of the
components being a liquid) are delivered (e.g., by the pumps 31 in
the illustrated embodiment) via the conduits 33 to the inlet ports
69a, 69b formed in the collar 61 of the treatment chamber housing
51. As these components enter the interior space 53 of the chamber
21 via the inlet ports 69a, 69b, the orientation of the inlet ports
induces a relatively swirling action to initiate mixing of these
components upstream of the horn assembly 105, such as in the fluid
intake zone of the interior space of the chamber. The liquid
solution flows upward within the chamber 21 past the waveguide
assembly 101 and through the bed of chamber particles 24 between
the waveguide assembly and the chamber sidewall 57.
[0087] The waveguide assembly 101, and more particularly the horn
assembly 105, is driven by the drive system 131 to vibrate
mechanically at a predetermined ultrasonic frequency. In response
to ultrasonic excitation of the horn 133, the agitating members 137
that extend outward from the outer surface 135 of the horn 133
dynamically flex/bend relative to the horn, or displace
transversely (depending on the longitudinal position of the
agitating member relative to the nodal region of the horn). When
using a horn assembly 205 such as that illustrated in FIG. 4 with
one of the agitating members 237 disposed at the nodal region of
the horn and having a longitudinal 241 component spaced
transversely from the horn, the longitudinal component of the
agitating member dynamically flexes/bends transversely relative to
the horn.
[0088] Liquid solution flows continuously longitudinally along the
flow path between the horn assembly 105 and the inner surface 67 of
the chamber sidewall 57 so that the ultrasonic vibration of the
agitating members 137 agitates the liquid solution (and, where
liquid solution comprises two or more components, also facilitates
mixing of the components). In particularly suitable embodiments,
the dynamic motion of the agitating members causes cavitation in
the liquid to further facilitate agitation of the liquid solution.
The ultrasonic energy imparted by the horn assembly 105 also acts
on the chamber particles 24 to promote relative motion of the
particles and to inhibit the particles against packing together,
i.e., to reduce the risk of reduced flow rate or pressure drop
within the ultrasonic treatment chamber 21. The vibratory motion
imparted to the particles 24 also reduces the hydrodynamic boundary
layer of around each particle to facilitate an increased reaction
rate (where a reaction of the liquid components, or reaction
between the liquid and the chamber particles such as adsorption, is
intended to occur) within the chamber 21.
[0089] Ultrasonic vibration of the waveguide assembly 101 also
generates high heat in the immediate area surrounding the waveguide
assembly surface. As a result, the liquid in the chamber that is
generally in contact with or immediately adjacent the surface of
the waveguide assembly 101 is substantially heated by the
ultrasonic vibration of the waveguide assembly. While the liquid
itself facilitates some conduction of heat from this immediate area
to the rest of the liquid flowing between the waveguide assembly
101 and the chamber sidewall inner surface 67, it cannot do so with
the same effectiveness as the higher thermal conductivity chamber
particles 24. Accordingly, the higher thermal conductivity chamber
particles 24 more rapidly conduct heat generated by the ultrasonic
waveguide assembly 24 throughout the liquid flowing through the bed
of particles between the waveguide assembly and the inner surface
67 of the chamber sidewall 57. This is particularly useful where
treatment of the liquid (e.g., mixing, reaction, etc.) involves
increasing the temperature of the liquid as it flows within the
chamber.
[0090] Ultrasonic operation of the waveguide assembly 101 also
generates (together with the reflector 301) a standing acoustic
wave (e.g., a one dimensional standing wave) in the liquid within
the buffer zone between the terminal end 103 of the waveguide
assembly and the reflector, with the one or more nodes of the
standing wave spaced longitudinally from the outlet port 65, and
more particularly from the screen element 66. With particular
reference to FIG. 5, as liquid flows up beyond the terminal end 103
of the waveguide assembly 101, it may carry some of the chamber
particles 24 into the buffer zone. The acoustic radiation of the
standing wave around these particles 24 urges the particles toward
the nearest dynamically stable position, which is the node of the
one-half wavelength standing wave (or node at each one-half
wavelength if the distance between the reflector 301 and waveguide
assembly 101 is a multiple of a one-half wavelength). The particles
24 thus become generally "trapped" at the node of the standing wave
away from the screen element 66 and outlet port 65 as illustrated
in FIG. 5 to thereby inhibit the particles against clogging the
screen element, and hence the outlet port, or otherwise reducing
the flow rate of liquid out of the chamber 21.
[0091] In some embodiments, particles 24 stabilized at the node of
the standing wave will agglomerate. As such an agglomeration
becomes heavier, the agglomerated particles will fall away from the
node and back (e.g., against the direction of flow through the
chamber) down into the main bed of particles in the chamber 21.
[0092] Where further agitation of the liquid in the chamber 21 is
desired, a baffle assemble (not shown) can be disposed within the
interior space 53 of the chamber, and in particular generally
transversely adjacent the inner surface 67 of the sidewall 57 and
in generally transversely opposed relationship with the horn
assembly 105. Such a baffle assembly may comprise one or more
baffle members disposed adjacent the inner surface 67 of the
chamber sidewall 57 and extending at least in part transversely
inward from the inner surface of the sidewall toward the horn
assembly 105 in interspaced relationship with the agitating members
137. These baffle members facilitate the flow of liquid
transversely inward over the ultrasonically vibrated agitating
members 137 of the horn assembly 105. One suitable baffle assemble
is described more fully in co-pending U.S. application Ser. No.
11/530,311 entitled ULTRASONIC LIQUID TREATMENT CHAMBER AND
CONTINUOUS FLOW MIXING SYSTEM and filed Sep. 8, 2006, the
disclosure of which is incorporated herein by reference to the
extent it is consistent herewith.
[0093] In another suitable embodiment, the sidewall 57 of the
ultrasonic treatment chamber 21 may be configured and arranged
relative to the waveguide assembly 101 to generate a standing
acoustic wave therebetween upon ultrasonic vibration of the
waveguide assembly. In particular, the chamber sidewall 57 may be
constructed of a material having an acoustical impedance that is
substantially greater than the liquid flowing within the chamber
21, and in particular along the flow path between the waveguide
assembly 101 and the chamber sidewall. The inner surface 67 of the
sidewall 57 is suitably spaced from the outer surface 135 of the
ultrasonic horn 133 a distance sufficient (based on the liquid in
the chamber 21 and the operating frequency of the waveguide
assembly 101) to generate a one-half wavelength standing wave
wherein the outer surface of the horn acts as a transducer and the
sidewall of the chamber acts as a reflector.
[0094] Upon operation of the waveguide assembly 101 a standing
acoustic wave is produced in the liquid between the horn outer
surface 135 and the sidewall inner surface 67. Such a standing wave
suitably has at least one node spaced from the sidewall inner
surface 67 and the horn outer surface 135. Chamber particles 24 in
the flow path are urged toward and generally stabilized or trapped
at the one or more nodes of the standing wave to inhibit particles
against stagnating against the sidewall 57 and/or against the horn
133, and to inhibit particles against being carried by the flow of
liquid downstream beyond the terminal end 103 of the waveguide
assembly 101 into the buffer zone.
[0095] In other embodiments, such as where the ultrasonic treatment
chamber 21 is used for mixing together two or more components to
form a liquid solution, it is contemplated that the chamber
particles 24 may be omitted (e.g., the chamber would resemble what
is illustrated in FIG. 2) without departing from the scope of this
invention. In such embodiments, the longitudinal standing wave
formed in the buffer zone of the chamber 21 (i.e., by the waveguide
assembly 101 and the reflector 301) is used to trap small
particulate contaminates that may be present in the liquid
components, thus effectively removing the contaminates from the
liquid solution before the solution exits the treatment
chamber.
[0096] When introducing elements of the present invention or
preferred embodiments thereof, the articles "a", "an", "the", and
"said" are intended to mean that there are one or more of the
elements. The terms "comprising", "including", and "having" are
intended to be inclusive and mean that there may be additional
elements other than the listed elements.
[0097] As various changes could be made in the above constructions
and methods without departing from the scope of the invention, it
is intended that all matter contained in the above description and
shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
* * * * *